Nuclear Srategy

The doctrine of nuclear deterrence that leaves open the possibility of launching a "first strike" before an enemy attacks will remain the basis of U.S. policy even as new generations of nuclear weapons are introduced, Defense Secretary Ashton Carter said Tuesday. "That's our doctrine now, and we don't have any intention of changing that doctrine," Carter told airmen in a question-and-answer session at Kirtland Air Force Base in New Mexico.